Abstract: The centrifugal force distributes non-uniformly with radius in centrifugal field. If the stress is set in two thirds height of a model according to the prototype, the error between the stresses of prototype and model can become minimum. The influence depth of model foundation is limited. So the error between stresses of prototypes and models should be considered in this range (the maximum influence depth). Therefore the condition which makes the minimum error between prototypes and models is to set the two thirds maximum influence depth rather than two thirds height of the model. The model height is inconsistent with the maximum influence depth for avoiding boundary effects. Its value is greater. The influences of centrifugal acceleration, similarity ratio and stress are discussed. The modified method of the similarity ratio determined before tests according to the model height is also introduced.